Flame-retardant fabric having high visibility

ABSTRACT

Provided is a flame-retardant fabric having a color that satisfies the criteria required by the international standard for high visibility ISO20471. The fabric includes polyetherimide-based fibers that contain a white pigment.

CROSS REFERENCE TO THE RELATED APPLICATION

This application is a continuation application, under 35 U.S.C § 111(a)of international application No. PCT/JP2017/027748, filed Jul. 31, 2017,which claims priority to Japanese patent application No. 2016-154254,filed Aug. 5, 2016, the entire disclosure of which is hereinincorporated by reference as a part of this application.

FIELD OF THE INVENTION

The present invention relates to a flame-retardant fabric that can beobtained by dyeing flame-retardant polyetherimide-based fiberscontaining a white pigment, the flame-retardant fabric having a colorthat satisfies the criteria required by the international standard forhigh visibility ISO20471 and having an improved tenacity retention rateof fiber after dyeing.

BACKGROUND OF THE INVENTION

Polyetherimide-based fibers are excellent in heat resistance and flameretardancy, and are very effectively used in many applications,including the industrial material field, the electric and electronicfield, the agricultural material field, the apparel field, the opticalmaterial field, and planes, automobiles and ships, etc.

In many applications with a central focus on the apparel field, not onlypolyetherimide-based fibers, but various highly-functional syntheticfibers are colored when they are used. In particular, there has beengrowing demand in applications to work clothing for outdoor constructionsites, outdoor work related to car accidents or the like, trafficguidance, traffic control, etc. for fiber products, such asflame-retardant garments, with high visibility and excellentlightfastness, which are colored with fluorescent colors and others toensure safety for the work.

Materials used in such highly visible fiber products are defined inaccordance with the international standard for high visibility ISO20471.This standard specifies criteria for color properties of materials basedon conditions known to this technical field, such as CIE chromaticitycoordinates and luminosity coefficients.

As a material that is applicable to the above applications, PatentDocument 1 (JP Laid-open Patent Publication No. 2013-32612) discloses aflame-retardant fabric containing aramid, viscose or polyimide fiberswhich has high visibility by printing. However, this fabric exhibitscolors only in printed portions, not in the entire fabric.

Patent Document 2 (JP Laid-open Patent Publication No. 2014-237905)describes a flame-retardant fabric containing polyetherimide-basedfibers, which satisfies the conditions of chromaticity coordinates andluminosity coefficients specified by the European standard for highvisibility EN471, which is equivalent to the international standard forhigh visibility ISO20471. However, in order to dye polyetherimide fibersto a color that satisfies the standard for high visibility, it isnecessary to dye the polyetherimide fibers under high-temperature andhigh-pressure conditions with a career that is a dyeing auxiliary. Onthis point, there is a problem that permeation of the dye and the careerto the polyetherimide-based fibers while dyeing makes the fiber surfacemore prone to damage, leading to considerable deterioration inmechanical property of the fibers.

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

The object of the present invention is to provide a flame-retardantfabric that solves the above-mentioned problem, satisfies theinternational standard for high visibility ISO20471 and has an improvedfiber tenacity retention rate.

Means for Solving the Problems

As a result of intensive investigation of the problem, the inventors ofthe present invention found that dyeing procedure of flame retardantpolyetherimide-based fibers in a condition that the fibers contain awhite pigment achieves to obtain a flame-retardant fabric that isexcellent in flame retardancy, has a color satisfying the criteriarequired by the international standard for high visibility ISO20471 andhas an improved retention rate of a fiber mechanical property, and theinventors thus achieved the present invention.

That is, the present invention is a flame-retardant fabric that includespolyetherimide-based fibers containing a white pigment and has a colorsatisfying the criteria required by the international standard for highvisibility ISO20471.

Alternatively, the fabric after dyeing (dyed fabric) may have a colorthat has CIE chromaticity coordinates (x, y) within a color spacedelimited by (0.624, 0.374), (0.589, 0.366), (0.609, 0.343) and (0.655,0.345), and a luminosity coefficient β equal to or greater than 0.40.

Alternatively, the fabric after dyeing may have a color that has CIEchromaticity coordinates (x, y) within a color space delimited by(0.450, 0.549), (0.420, 0.483), (0.375, 0.528) and (0.395, 0.602), and aluminosity coefficient β equal to or greater than 0.70.

Furthermore, the fabric may be a fabric that includespolyetherimide-based fibers having a fiber tenacity retention rate of65% or higher.

Moreover, the present invention is a method for producing apolyetherimide-based fiber, the method including dyeing apolyetherimide-based fiber containing a white pigment at a temperaturefrom 100° C. to 125° C. to give the fiber a color satisfying thecriteria required by the international standard for high visibilityISO20471.

Effect of the Invention

The present invention can provide a flame-retardant fabric thatsatisfies the international standard for high visibility ISO20471 andhas an improved fiber tenacity retention rate.

DESCRIPTION OF THE EMBODIMENTS

The present invention is characterized by that the flame-retardantfabric having a color satisfying the criteria required by theinternational standard for high visibility ISO20471 and an improvedfiber tenacity retention rate. The flame-retardant fabric can beobtained by dyeing polyetherimide-based fibers having excellent flameretardancy wherein a white pigment is added to the fibers.

Polyetherimide-Based Resin

Examples of polyetherimide-based resins used in the present inventionmay include polymers containing a combination of repeating structuralunits represented by the following formula. In the formula, R1represents a divalent aromatic residue having 6 to 30 carbon atoms, andR2 represents a divalent organic group selected from the groupconsisting of a divalent aromatic residue having 6 to 30 carbon atoms,an alkylene group having 2 to 20 carbon atoms, a cycloalkylene grouphaving 2 to 20 carbon atoms, and a polydiorganosiloxane group in whichthe chain is terminated by an alkylene group having 2 to 8 carbon atoms.

The preferable R1 and R2 include, for example, an aromatic residue andan alkylene group (e.g., m=2 to 10) shown in the following formulae.

In the present invention, from the viewpoint of an amorphous property,melt formability, and cost reduction, a preferable polymer includes acondensate of 2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydrideand m-phenylenediamine, having a structural unit shown by the followingformula as a main constituent. Such an amorphous polyetherimide isavailable from SABIC Innovative Plastics Holding under the trademark of“ULTEM”.

The polyetherimide-based resin used in the present invention preferablyhas a molecular weight distribution (Mw/Mn) smaller than 2.5. Amolecular weight distribution equal to or greater than 2.5 may be notpreferable because of poor spinnability.

White Pigment

The inventors have found that dyeing of a polyetherimide-based fibercontaining, for example, 0.5 to 5.0% owf (on the weight of fiber) of, awhite pigment enables to enhance luminosity required by theinternational standard for high visibility A content less than 0.5% owfmay be not preferable because the content of the white pigment dispersedin the fiber resin may be low to exhibit sufficient luminosity in thefiber after dyeing. A content greater than 5.0% owf may be notpreferable because additives may be more likely to coagulate to decreasespinnability.

The white pigment used in the present invention may include anatasetitanium oxide, rutile titanium oxide, zinc oxide, calcium carbonate,zirconium oxide, basic carbonate, and calcium sulfate dihydrate. Themost preferable pigment is anatase titanium oxide, which has the highestreflectance rate at wavelengths in the visible region.

Dye

The dye used in the present invention may be any disperse dye as long asthe dye is capable of dyeing a conventional polyester fiber and is notparticularly limited. As the disperse dye particularly suitable forpolyetherimide-based fibers, there may be mentioned a disperse dye thathas a good diffusion property, has a higher inorganic property in aratio of inorganic/organic properties and typically contains hydroxylgroup or a halogen atom. Examples of preferable dyes forpolyetherimide-based fibers may include “Dianix Yellow AM-42,” “DianixLuminous Yellow GN” and “Dianix Luminous Yellow 10G” as yellow dyes;“Kayalon Brilliant Orange HL-SF200,” “Reform Brilliant Orange CV-N” and“Dianix Orange AM-SLR” as orange dyes; and “Dianix Br. Scarlet SF” as ared dye. Some of the dyes mentioned above are capable of dyeing fiberssuccessfully without a carrier. Use of a carrier makes it possible toachieve deep shade and also improved washfastness. In addition, thespecies of dyes to be used in the present invention is not particularlylimited to the above-mentioned dyes because use of a carrier makes itpossible to achieve successful dyeing with some of the dyes which do notachieve successful dyeing without a carrier.

Career

In the present invention, it is preferable to use a phthalimidecompound, a benzyl alcohol compound, a chlorobenzene compound, amethylnaphthalene compound, or the like as a career. These careers maybe singly used, or may be used in combination to make it possible toproduce deeper shades. The following careers, for example, arecommercially available: as a phthalimide career “Dye Career TN-55”(manufactured by DAIWA CHEMICAL INDUSTRIES Co., Ltd.); as a benzylalcohol career “benzyl alcohol” (manufactured by Tokyo Chemical IndustryCo., Ltd.); as a chlorobenzene career “IPC-71P Career C-71”(manufactured by Ipposha Oil Industries Co., ltd.); and as amethylnaphthalene career “Tetrosin AT-M” (manufactured by YamakawaChemical Industry Co., Ltd.).

Color

The flame-retardant fabric of the present invention is characterized byhaving a color that satisfies the criteria required by the internationalstandard for high visibility ISO20471. The international standard forhigh visibility ISO20471 specifies the criteria based on conditions suchas CIE chromaticity coordinates and a CIE tristimulus value for eachcolor type used in a material. That is, the standard requires a redmaterial to have CIE chromaticity coordinates (x, y) within a colorspace delimited by (0.655, 0.345), (0.570, 0.340), (0.595, 0.315) and(0.690, 0.310), and a luminosity coefficient β equal to or greater than0.25. Similarly, an orange-red material has to have CIE chromaticitycoordinates within a color space delimited by (0.610, 0.390), (0.535,0.375), (0.570, 0.340) and (0.655, 0.345), and a luminosity coefficientβ equal to or greater than 0.40. A yellow material has to have CIEchromaticity coordinates within a color space delimited by (0.387,0.610), (0.356, 0.494), (0.398, 0.452) and (0.460, 0.540), and aluminosity coefficient β equal to or greater than 0.70.

It is essential that fabric products in the condition immediately afterdyeing satisfy the criteria required by the international standard forhigh visibility ISO20471 when the products are used for applicationsthat require high visibility. In addition, it is preferable thatmaterials are less susceptible to discoloration due to variousenvironmental factors, e.g., light, or that materials still satisfy thecriteria required by the international standard for high visibilityISO20471 even after discoloration occurs. Accordingly, if theflame-retardant fabric of the present invention is an orange-redmaterial, the flame-retardant fabric after dyeing preferably has a colorof CIE chromaticity coordinates (x, y) within a color space delimited by(0.624, 0.374), (0.589, 0.366), (0.609, 0.343) and (0.655, 0.345), andof a luminosity coefficient β equal to or greater than 0.40. Theflame-retardant fabric of the present invention which is dyed to a colorwithin the color space can have a chromaticity within the color spacespecified for an orange-red material by the international standard forhigh visibility ISO20471 even after the fabric is exposed to light.

Similarly, if the flame-retardant fabric of the present invention is ayellow material, the flame-retardant fabric after dyeing preferably hasa color of CIE chromaticity coordinates (x, y) within a color spacedelimited by (0.450, 0.549), (0.420, 0.483), (0.375, 0.528) and (0.395,0.602), and of a luminosity coefficient β equal to or greater than 0.70.The flame-retardant fabric of the present invention which is dyed to acolor within the color space can have a chromaticity within the colorspace specified for a yellow material by the international standard forhigh visibility ISO20471 even after the fabric is exposed to light.

Furthermore, it is preferable in the present invention that a whitepigment is uniformly dispersed in desired polyetherimide-based fibers.White pigment dispersed in the fibers enables light penetrating insidethe dyed polyetherimide-based fibers to be scattered and reflected tothe surface of the fiber, and thereby the white pigment allows thefibers to have a higher luminosity than that of fibers without whitepigment. Thanks to the luminosity-enhancing effect, it is possible todye fibers at a lower temperature than the dyeing temperature requiredin Patent Document 2, and thus, it is possible to obtain aflame-retardant fabric that has a luminosity satisfying the criteriarequired by the international standard for high visibility ISO20471 andis suppressed in deterioration in mechanical properties due to dyeing.The preferable range of dyeing temperatures is from 100° C. to 125° C.,and more preferably from 110° C. to 120° C.

Method for Fiber Formation

Next, the method for forming fibers will be described. A fiber-formableresin is melt-extruded into a fibrous shape by using a single-screw ortwin-screw extruder through a nozzle having a diameter of 0.1 to 10.0mm. The resultant fiber is wound at a speed from 300 m/min to 3,000m/min to produce a fiber of 0.1 to 1000 dtex.

Method for Adding White Pigment

Fibers containing a certain amount of a white pigment can be obtained bya method in which melt-spinning of a fiber-formable resin is carried outwith adding a white pigment during melt-spinning procedure, or in whichmelt-spinning is carried out by using a fiber-formable resin containingwhite pigment that is added before melt-spinning. It is preferable toprepare a master batch by melt-mixing a resin and a white pigment sothat the master batch and a fiber-formable resin are melt-knead in orderto improve dispersibility of the white pigment.

Fabric

In the present invention, the polyetherimide-based fiber can be used toobtain a flame-retardant fabric with high visibility, that can be anytype of fabric, including woven fabrics, knitted fabrics, and nonwovenfabrics.

Applications

The flame-retardant fabric of the present invention which satisfies thecriteria required by the international standard for high visibilityISO20471 and is capable of having a tenacity retention rate equal to orgreater than 65% can be applied to a wide range of applications thatrequire flame retardancy and high visibility, such as protectiveclothing and/or accessories.

EXAMPLES

Hereinafter, the present invention will be more specifically explainedwith reference to examples. However, the present invention is not to beconstrued as being limited by these examples. It should be noted thatflame resistance, chromaticity and luminosity, lightfastness andtenacity retention rates were evaluated in the following manners in theExamples described below.

Evaluation of Flame Resistance

In accordance with JIS K7201, samples each tied into a braid and havinga length of 18 cm were prepared. After igniting the upper portion of thesamples, the minimum oxygen concentration [limiting oxygen index (LOI)value] required for the samples to keep burning for at least 3 minutesor alternatively to be burned until the burning length of the samplereaches at least 5 cm was determined. The average of 3 samples (n=3) wasadopted.

Evaluation of Chromaticity and Luminosity

For each tubular knitted fabric after dyeing, the CIE chromaticitycoordinates (x, y) and the luminosity coefficient β of reflected lightwere measured using “Spectrophotometer 3700d” manufactured by MinoltaCo., Ltd. so as to evaluate chromaticity and luminosity.

Evaluation of Lightfastness

The xenon lamp irradiation test was performed using “7.5-kW Super XenonWeather Meter SX75” manufactured by Suga Test Instruments Co., Ltd. inaccordance with ISO105-B02. The xenon light fastness was determined bythe 3rd exposure method of ISO105-B02: 1994. As for the orange-red colorsamples, light was irradiated until the blue standard fabric with level5 reaches grade 3 of gray scale. As for the yellow color samples, lightwas irradiated until the blue standard fabric with level 4 reaches grade4 of gray scale.

Evaluation of Tenacity Retention Rate

For each single fiber forming the tubular knitted fabric before andafter dyeing, single fiber tenacity was measured by using an automatictensile testing device for short fibers “AMS-C TENSHILON/UTM-II-20”manufactured by Orientec Co., Ltd., and the average of 10 samples (n=10)was adopted. The fiber tenacity retention rate was calculated by thefollowing formula.

Fiber tenacity retention rate=(Average single fiber tenacity afterdyeing)/(Average single fiber tenacity before dyeing)×100(%)

Example 1

“ULTEM 9011” manufactured by SABIC Innovative Plastics Holding(amorphous PEI system resin having a weight-average molecular weight(Mw) of 32,000, a number-average molecular weight (Mn) of 14,500 and amolecular weight distribution (Mw/Mn) of 2.2) was used as apolyetherimide resin. Hereinafter, the resin is abbreviated as “U-PEIresin.” After kneading 95 parts by mass of the U-PEI resin and 5 partsby mass of the U-PEI master batch resin containing 10% owf of anatasetitanium oxide relative to the U-PEI resin, the mixture wasmelt-extruded at 400° C., measured by a gear pump, and dischargedthrough a nozzle having a hole diameter Φ of 0.2 mm, and then was woundat a speed of 1500 m/min to produce fibers of 84 dtex/24 f. Thusobtained fibers were formed into a tubular knitted fabric. The resultanttubular knitted fabric was placed in a sealable pressure-resistantstainless container together with the following dyeing solutioncontaining dyes, a career and a UV absorber, etc. and then was dyed for40 minutes at 115° C. The dyed tubular knitted fabric was subjected toreduction cleaning for 20 minutes at 80° C. in a reduction cleaning bathas described below so as to remove impurities on the fiber surfaces.

Formulation and Liquid Volume of Dyeing Solution

Tubular knitted fabric of polyether imide fibers: 10 g

Ultra MT level [pH adjusting agent] (manufactured by Mitejima ChemicalCo., Ltd.): 1 g/L

Reform Brilliant Orange CV-N [orange dye] (manufactured by NIKKA FINETECHNO CO., LTD.): 3.5% owf

Dianix Luminous Yellow GN [yellow dye] (manufactured by DyStar JapanLtd.): 0.5% owf

TN-55 [career]: 4% owf

Briand FOK-3 [ultraviolet absorber] (manufactured by MatsumotoYushi-Seiyaku Co., Ltd.): 3% owf

Total liquid volume: 200 cc

Formulation of Reduced Cleaning Solution

Sodium carbonate: 1 g/L

Hydrosulfite: 1 g/L

Amirajin D (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.): 1 g/L

Liquid volume: 200 cc

Example 2

After kneading 90 parts by mass of the U-PEI resin and 10 parts by massof the U-PEI master batch resin containing 10% owf of anatase titaniumoxide relative to the U-PEI resin, the mixture was melt-extruded at 400°C., measured by a gear pump, and discharged through a nozzle having ahole diameter Φ of 0.2 mm, and then was wound at a speed of 1500 m/minto produce fibers of 84 dtex/24 f. Thus obtained fibers were formed intoa tubular knitted fabric. The resultant tubular knitted fabric was dyedand subjected to reduction cleaning under the same conditions as thoseof Example 1.

Example 3

After kneading 80 parts by mass of the U-PEI resin and 20 parts by massof the U-PEI master batch resin containing 10% owf of anatase titaniumoxide relative to the U-PEI resin, the mixture was melt-extruded at 400°C., measured by a gear pump, and discharged through a nozzle having ahole diameter Φ of 0.2 mm, and then was wound at a speed of 1500 m/minto produce fibers of 84 dtex/24 f. Thus obtained fibers were formed intoa tubular knitted fabric. The resultant tubular knitted fabric was dyedand subjected to reduction cleaning under the same conditions as thoseof Example 1.

Example 4

After kneading 50 parts by mass of the U-PEI resin and 50 parts by massof the U-PEI master batch resin containing 10% owf of anatase titaniumoxide relative to the U-PEI resin, the mixture was melt-extruded at 400°C., measured by a gear pump, and discharged through a nozzle having ahole diameter Φ of 0.2 mm, and then was wound at a speed of 1500 m/minto produce fibers of 84 dtex/24 f. Thus obtained fibers were formed intoa tubular knitted fabric. The resultant tubular knitted fabric was dyedand subjected to reduction cleaning under the same conditions as thoseof Example 1.

Example 5

After kneading 90 parts by mass of the U-PEI resin and 10 parts by massof the U-PEI master batch resin containing 10% owf of zinc oxiderelative to the U-PEI resin, the polyetherimide resin containing zincoxide whose content was adjusted to 0.5% by weight was melt-extruded at400° C., measured by a gear pump, and discharged through a nozzle havinga hole diameter Φ of 0.2 mm, and then was wound at a speed of 1500 m/minto produce fibers of 84 dtex/24 f. Thus obtained fibers were formed intoa tubular knitted fabric. The resultant tubular knitted fabric was dyedand subjected to reduction cleaning under the same conditions as thoseof Example 1.

Example 6

A tubular knitted fabric was prepared in the same conditions as those ofExample 2 and was dyed under the same conditions as those of Example 2,except that the dye was changed to Dianix Luminous Yellow GN (1.0% owf).

Comparative Example 1

The U-PEI resin was independently melt-extruded at 400° C., measured bya gear pump, and discharged through a nozzle having a hole diameter Φ of0.2 mm, and then was wound at a speed of 1500 m/min to produce fibers of84 dtex/24 f. Thus obtained fibers were formed into a tubular knittedfabric. The resultant tubular knitted fabric was dyed and subjected toreduction cleaning under the same conditions as those of Example 1.

Comparative Example 2

A tubular knitted fabric prepared under the same conditions as those ofComparative Example 1 was placed in a sealable pressure-resistantstainless container together with a dyeing solution containing the samedyes, career and UV absorber, etc. to those of Example 1 and was dyedfor 40 minutes at 135° C. The dyed tubular knitted fabric was subjectedto reduction cleaning for 20 minutes at 80° C. in a reduction cleaningbath as described above so as to remove impurities on the fibersurfaces.

Comparative Example 3

A tubular knitted fabric prepared under the same conditions as those ofComparative Example 1 was placed in a sealable pressure-resistantstainless container together with a dyeing solution containing the samedye, career and UV absorber, etc. as those of Example 6 and was dyed for40 minutes at 135° C. The dyed tubular knitted fabric was subjected toreduction cleaning for 20 minutes at 80° C. in a reduction cleaning bathas described above so as to remove impurities on the fiber surfaces.

TABLE 1 Addi- After lightfastness tion Orange Yellow Dyeing TenacityAfter dyeing evaluation White amount dye dye temp. Dye retentionLuminosity Luminosity pigment (% owf) (% owf) (% owf) (° C.) color LOIrate (%) x y coef. β x y coef. β Example 1 Titanium 0.5 3.5 0.5 115Orange- 32 67.8 0.601 0.360 0.428 0.558 0.373 0.448 oxide red Example 2Titanium 1.0 3.5 0.5 115 Orange- 32 67.5 0.604 0.359 0.430 0.561 0.3720.450 oxide red Example 3 Titanium 2.0 3.5 0.5 115 Orange- 33 67.2 0.6020.360 0.444 0.559 0.373 0.464 oxide red Example 4 Titanium 5.0 3.5 0.5115 Orange- 32 65.6 0.595 0.361 0.452 0.547 0.374 0.472 oxide redExample 5 Zinc 1.0 3.5 0.5 115 Orange- 32 67.0 0.594 0.365 0.423 0.5470.363 0.443 oxide red Example 6 Titanium 1.0 — 1.0 115 Yellow 32 67.80.406 0.540 0.910 0.402 0.524 0.830 oxide Comparative — — 3.5 0.5 115Orange- 32 76.8 0.585 0.360 0.384 0.542 0.373 0.429 Example 1 redComparative — — 3.5 0.5 135 Orange- 32 48.3 0.600 0.358 0.422 0.5560.371 0.442 Example 2 red Comparative — — — 1.0 135 Yellow 32 49.7 0.4380.525 0.730 0.421 0.511 0.764 Example 3

Table 1 shows the evaluation results for the tubular knitted fabricsobtained in Examples 1-6 and Comparative Examples 1-3. The tubularknitted fabrics of Examples 1-6 were evaluated as having flameretardancy, being high in fiber tenacity retention rate, and havingcolors that satisfied the criteria required by the internationalstandard for high visibility ISO20471 after dyeing as well as after thelightfastness evaluation. The tubular knitted fabric of ComparativeExample 1 was evaluated as not having a color that satisfied thecriteria required by the international standard for high visibilityISO20471 after dyeing because the polyetherimide-based fiber withoutwhite pigment was dyed at 115° C. The tubular knitted fabrics ofComparative Examples 2 and 3 were evaluated as having low tenacityretention rates of the polyetherimide-based fibers constituting thefabrics because the polyetherimide-based fibers without white pigmentwere dyed at 135° C.

INDUSTRIAL APPLICABILITY

The flame-retardant fabric according to the present invention whichcontains polyetherimide-based fibers with at least one additive selectedfrom a group consisting of white pigments at a certain amount has highluminosity. Therefore, the fabric can be used as highly visibleprotective clothing and/or accessories that require flame retardancyand, thus, is industrially applicable in the fields of manufacturingand/or processing the fibers.

The preferred embodiments according to the present invention have beendescribed above, but those skilled in the art would readily conceive ofvarious changes and modifications within the obvious range in view ofthe present specification. Accordingly, such changes and modificationsare construed as within the scope of the invention as defined from thescope of the claims.

What is claimed is:
 1. A flame-retardant fabric comprisingpolyetherimide-based fibers containing a white pigment, the fabrichaving a color that satisfies the criteria required by the internationalstandard for high visibility ISO20471.
 2. The flame-retardant fabricaccording to claim 1, wherein the fabric after dyeing has a color thathas CIE chromaticity coordinates (x, y) within a color space delimitedby (0.624, 0.374), (0.589, 0.366), (0.609, 0.343) and (0.655, 0.345),and a luminosity coefficient β equal to or greater than 0.40.
 3. Theflame-retardant fabric according to claim 1, wherein the fabric afterdyeing has a color that has CIE chromaticity coordinates (x, y) within acolor space delimited by (0.450, 0.549), (0.420, 0.483), (0.375, 0.528)and (0.395, 0.602), and a luminosity coefficient β equal to or greaterthan 0.70.
 4. The flame-retardant fabric according to claim 1, whereinthe fabric comprises polyetherimide-based fibers having a fiber tenacityretention rate of 65% or higher.
 5. The flame-retardant fabric accordingto claim 1, wherein the polyetherimide-fiber contains the white pigmentat a concentration of 0.5 to 5.0% owf.
 6. A method for producing apolyetherimide-based fiber, the method comprising dyeing apolyetherimide-based fiber containing a white pigment at a temperaturefrom 100° C. to 125° C. to give the fiber a color that satisfies thecriteria required by the international standard for high visibilityISO20471.
 7. The method according to claim 6, wherein the given fibersatisfies a fiber tenacity retention rate of 65% or higher.